For some applications, such as aircraft propulsion, performance specifications dictate that gas turbine engines have operational capability for a predetermined, limited duration after the oil supply from the usual main oil pump of the engine is interrupted. In prior proposals for secondary oil systems for sustaining engine operation for the aforesaid limited duration, oil from a separate reservoir on the engine is conducted to a point of use by centrifugal force induced pressure, by gravity or by air pressure. In other proposals, the oil is aspirated from the separate reservoir by a stream of high velocity air. Usually, the oil from the separate reservoir is dispersed as a mist or maximizing the duration of engine operation after main pump interruption. In a gas turbine engine oil system according to this invention, the portion of the oil system between the main pump discharge and the points of application defines an integral reservoir from which oil is recirculated by the engine's scavenge pumps in the absence of main pump discharge.